A group has sued to block a north San Diego mall from beginning construction on its long-awaited expansion project.

The Flower Hill Promenade, just outside Solana Beach and east of Del Mar, plans to add a 35,000-square-foot Whole Foods Market, 25,000 square feet of office space and 8,700 square feet of retail shops. The San Diego City Council approved the project last month after more than six years of planning, design and adjustments.

The expansion would also add a four-level parking garage. An Ultrastar movie theater would be demolished to make room for the new development.

A group called the Citizens Against Flower Hill’s Excessive Expansion filed the lawsuit last week to overturn the City Council’s approval of the project. The suit generally contends the expansion’s environmental impact report was inadequately vetted given the mall’s location next to coastal wetlands.

Robert Vicino, who lives above the mall, is leading the lawsuit. He called the project “overscaled” and said he doesn’t believe it will ultimately get built as approved.

San Diego city spokesman Alex Roth said he could not comment on pending litigation. Flower Hill spokesman Chris Wahl said the ownership stands behind the expansion and believes courts will as well. Construction is slated to begin in June.

The group’s lawsuit is not the only potential legal battle facing the Flower Hill Promenade. There is also an ongoing dispute between the California Coastal Commission and the city over who should have had the authority to approve the project. Deborah Lee, the commission’s San Diego district director, said last week the state agency would take steps to gain jurisdiction over Flower Hill.